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Title: Applications of modified plant extracts in controlling parasites
Author: Ahmad, Nema Ali
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 2013
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Parasitic diseases remain a major public health problem affecting hundreds of millions of people, particularly in tropical developing countries. Pharmaceutical research in natural products represents a major strategy for discovering and developing new drugs. The use of medicinal plants for the treatment of parasitic diseases is well known and documented since ancient times. Saponins are a structurally diverse class of compounds occurring in many plant species, and possessing a number of desirable biological and pharmacological activities. In this work methodology was developed to extract, isolate and purify desirable triterpenoid saponins based on the unusual aglycone backbone hederagenin from the fruits and leaves of common ivy (Hedera helix) and by chemical modification of the glycosides and aglycone, further derivatives were prepared. These novel compounds which were used to conduct trials of their biological activities to identify the best means of optimising these activities. The goal was to identify effective antileishmanial, antiacanthamoebal and antiplant parasitic agents from plant sources using a systematic approach. The compounds were evaluated against Leishmania major, Leishmania mexicana and Leishmania donovani. This study concluded that modified triterpenoid saponins from Hedera helix show promising in vitro and in vivo activity against promastigote and amastigote stages and can be considered as new lead structures in the search for novel antileishmanial drugs. Some compounds showed a remarkable amoebicidal effect on Acanthamoeba castellanii. These compounds had been tested against plants parasitic and were found to be moderately effective in reducing egg hatching and mortality of the second juveniles. Four derivatives of eugenol were studied for their antileishmanial activity against L. major and L. mexicana. These results showed moderate activity. The project also determined the effect ofbioactive plant extract against in controlling microbial growth for three kinds of bacteria, Pseudomonas aeruginosa, Eschericha coli, and Staphylococcus aureus. One type of fungus, Candida albicans was also examined. The results had activity against bacterial and fungal infections and could be used to control these organisms.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available